Abstract: The main objective of this work is to study the computation of coupling on wires enclosed in the cavity with apertures by exciting sources. The analytical approach is rigorous and slow implementations. The numerical technique is too approximate to be useful. This paper presents a semi-analytical and semi-numerical approach based on method of moments-Green’s function (MoM-GF) technique and BLT equation. The MoM-GF technique is sufficiently accurate to simulate the equivalent magnetic flux to give the electromagnetic field in the cavity. And the formulas to compute the induced voltage and induced current of the two wire lines, terminations are derived employing the BLT equation based on Taylor model. The simulation on electric field shielding effectiveness of the cavity with apertures is co